知母-黄柏药对改善D-半乳糖诱导衰老小鼠认知障碍的机制研究OA北大核心CSTPCD

Objective:To study the improving effect of Anemarrhenae Rhizoma-Phellodendri Chinensis Cortex herb pair(Zhi Bai)on cognitive impairment in D-galactose(D-gal)administered mice,and to explore the mechanism of Zhi Bai in improving cog-nitive impairment through the AMPK/mTOR signaling pathway.Methods:Seventy-five C57BL/6J mice were randomly divided into five groups:the control group,the model group(D-gal 125 mg/kg),the piracetam group(468 mg/kg),the Zhi Bai group(4.5 g/kg),and the mTOR inhibitor group(everolimus,RAD001,3 mg/kg),with 15 mice in each group.The aging mouse model was established using D-gal,followed by 8 weeks of oral administration of Zhi Bai decoction.Cognitive functions in aging mice were assessed using the Morris water maze and novel object recognition tests.Hippocampal tissue pathology was observed us-ing hematoxylin and eosin(H&E)staining;neuronal and synaptic pathological morphology in the hippocampal region was exam-ined with Nissl and Golgi staining.Hippocampal tissues were collected to determine the levels of adenosine triphosphate(ATP)in the brain.The protein expression levels of ubiquitin-binding protein 62(P62),Beclin-1 associated with myosin,light chain kinase BCL2(Beclin-1),synaptophysin(Syn),postsynaptic density protein-95(PSD-95),AMP-activated protein kinase(AMPK),and mTOR in the hippocampus were detected by Western blot.The gene expression levels of Syn,AMPK,and mTOR in the hip-pocampus were measured using quantitative real-time PCR(qRT-PCR).Results:Compared to the control group,the model group mice showed significant cognitive impairment in the Morris water maze and novel object recognition tests(P<0.01).In the model group,there was a reduction in cell numbers,loose cell arrangement,and irregular neuronal morphology,a significant de-crease in Nissl bodies,and a decrease in dendritic branch and spine density in the hippocampal region.ATP levels,as well as P62,Syn,PSD-95,and mTOR protein expressions in the hippocampus of the model group,were significantly reduced(P<0.01),while Beclin-1 expression was significantly increased(P<0.01).The ratio of pAMPK to AMPK protein content and the expres-sion of AMPK genes were significantly elevated(P<0.01),whereas Syn and mTOR gene expressions were significantly de-creased(P<0.01).Compared to the model group,cognitive function was significantly improved in the piracetam and Zhi Bai groups,as evidenced by a significant reduction in the latency period in the Morris water maze test(P<0.01),increased platform crossing numbers and target quadrant dwell time(P<0.01),and a significant increase in the novel object recognition index(P<0.01).Dendritic spine density in the hippocampal region was significantly increased(P<0.01),and neuronal damage was alleviat-ed to some extent.ATP levels and P62,Syn,PSD-95,and mTOR protein expressions in the hippocampus were significantly in-creased(P<0.01,P<0.05),Beclin-1 protein expression was significantly reduced(P<0.01),and the ratio of pAMPK to AMPK protein content and AMPK gene expression were significantly decreased(P<0.01,P<0.05),with Syn and mTOR gene expressions significantly elevated(P<0.01).The results for the RAD001 inhibitor group were similar to the model group,but Zhi Bai treatment led to a recalibration of these indicators.Conclusion:Zhi Bai may inhibit excessive autophagy of neurons,enhance synaptic plasticity and improve D-gal-induced cognitive impairment in mice by activating the AMPK/mTOR signaling pathway.